United face Benfica in their final group match for the second season running, knowing another defeat would dump them out of the group stage once more.

"I am in shock," said Ferguson.

"Our home form has been very good.

"I have no worries on that score. We have to be a bit more aggressive and take our chances.

"Unfortunately we have a couple of big matches to play before then. We can focus on those and put the Champions League on the back burner."

Ferguson was referring to Sunday's crucial Premiership encounter with Chelsea at Old Trafford, when a win would put United six points clear at the top of the table.

Besides his penalty miss, Saha also wasted a major chance when he believed he had been flagged offside when in fact play had been waved on. "Louis thought he heard a whistle," conceded Ferguson.

"He is obviously disappointed to miss the penalty but the players will help to lift him because we are all together at this club.

"There are no problems with the boy. I am sure he will miss another penalty in his career at some point.

"Understandably, the players are disappointed. We have five days to lift them but if we want to win the league we have to show character and I am sure we will."

Ferguson insisted despite the result his team had not failed in his home city, believing they had come as close as it was possible to becoming only the second side to defeat Celtic at Parkhead in the Champions League.

"Benfica came here and melted in that atmosphere, we didn't. Historically, we have always had to do things the hard way at this football club. It looks like we will have to do it the hard way again."